Trace element concentrations in the troposphere and lower stratosphere

A technique has been developed and applied to establish the gradient of several trace elements from the troposphere through the lower stratosphere. U.S. Air Force planes during routine sampling flights performed aerosol collections over a two-year period at altitudes of 3 to 15 km between 37°N and 46°N. The concentrations of Ag, Co, Cr, Fe, Sb, Sc, and Zn measured by instrumental neutron-activation analysis showed gradients of tenfold to one hundredfold over the altitude range. Concentrations at a given altitude varied by severalfold as a function of time. A comparison of the relative concentrations observed in the atmosphere with those in metropolitan aerosols, the earth's crust, sea water, and rainwater collected at points remote from possible sources of pollution indicates that, although the atmospheric Fe, Co, and Sc are compatible with the injection of material from the earth's crust, the concentrations of Ag, Cr, Sb, and Zn in the atmosphere are too high to have originated from the natural sources considered. Of nineteen elements measured in rainwater, it appears that the only elements that could originate primarily from the oceans are Na, Cl, and Br.